Quantum Transport Detected by Strong Proximity Interaction
at a Graphene–WS<sub>2</sub> van der Waals Interface
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Abstract
Magnetotransport measurements demonstrate
that graphene in a van der Waals heterostructure is a sensitive probe
of quantum transport in an adjacent WS<sub>2</sub> layer via strong
Coulomb interactions. We observe a large low-field magnetoresistance
(≫ <i>e</i><sup>2</sup>/<i>h</i>) and a
−ln <i>T</i> temperature dependence of the resistance.
In-plane magnetic field resistance indicates the origin is orbital
and nonclassical. We demonstrate a strong electron–hole asymmetry
in the mobility and coherence length of graphene demonstrating the
presence of localized Coulomb interactions with ionized donors in
the WS<sub>2</sub> substrate, which ultimately leads to screening
as the Fermi level of graphene is tuned toward the conduction band
of WS<sub>2</sub>. This leads us to conclude that graphene couples
to quantum localization processes in WS<sub>2</sub> via the Coulomb
interaction and results in the observed signatures of quantum transport.
Our results show that theoretical descriptions of the van der Waals
interface should not ignore localized strong correlations